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Water quality data indicates that prior to 1995 there were no significant influences from discharges from disturbed <br />areas to Fish Creek upstream of alluvial monitoring wells. Water quality is characterized by sodium bicarbonate <br />dominance, total dissolved solids concentrations on the order of 760 mg/l, and a tendency for dominance of <br />• sodium, calcium and sulfate. <br />Well data indicates some mining influence on water quality over the period 1995 to date. When compared with <br />upstream alluvial Well 006 -AY -1 (Figure 4j), Well 006 -AZ -3 (Figure 4k), located downstream of discharge site <br />115, has exhibited an increasing trend in conductivity (1,300 to 1,800 umhos /cm) and total dissolved' solids (600 to <br />1,500 mg/1) since 1995. This is not as readily apparent in the alluvial wells located downstream of 006 -AZ -3. <br />Water quality data for the alluvial wells also exhibits seasonal fluctuations, reflecting recharge of the alluvium <br />during spring runoff. <br />(a), The application shall contain additional information, which -describes the rechatge, storage, and <br />discharge characteristics of aquifers and the quality and quantity of ground water for the proposed <br />permit and adjacent areas, according to the parameters and in the detail required by the Division. The <br />application shall also provide well locations and reported yields from all wells within the'proposed <br />permit and adjacent areas, which are registered with the Office of the State Engineer. <br />Twentymile Park, which includes the proposed permit and adjacent areas, lies within a semi =arid climatic, zone <br />with an average annual precipitation of only 16 inches. With the exception of the spring snowmelt, which results <br />primarily in surface runoff, most of the precipitation received is lost through evapotranspiration and sublimation. <br />As a result, the amount of precipitation available for groundwater recharge is limited. <br />All ground water aquifers in the general area, except the alluvial aquifers, are recharged by infiltration in outcrop <br />areas. Outcrop areas for the principal groundwater aquifers are shown on the Twentymile Sandstone <br />Potentiometric Surface Map (Map 33). <br />• BEDROCK AQUIFERS <br />The configuration of the potentiometric surface for the Wadge overburden aquifer (Map 13, Twentymile Park <br />Hydrology) indicates the direction of ground water movement in this unit. Ground water movement is generally <br />oriented perpendicular to the potentiometric contours in the direction of decreasing potentiometric elevation. The <br />map indicates that ground water tends to move from the recharge areas at the outcrops of these units, near the <br />southern and western margins of Twentymile Park Basin, toward the center of the basin, reflecting the structural <br />dip of the lithologic units. The general trend of movement in the permit area is to the north and northwest. <br />Discharge from the Wadge overburden to alluvial aquifers and surface streams, is believed to occur in the vicinity <br />of the outcrop area in the eastern and northeastern margins of the basin. A major fault zone in this area may be a <br />significant conduit for much of this discharge. <br />Ongoing monitoring and a series of pump tests conducted by various government agencies and independent <br />consultants have delineated characteristics of the Wadge Overburden in the permit and adjacent areas. The pump <br />tests were conducted under a broad range of conditions and varied in duration from 30 minutes to 72 hours. The <br />characteristics of specific intervals within the Wadge Overburden were tested utilizing temporary well packers and <br />monitoring variations in water levels and flows in adjacent observation wells with continuous water level and <br />discharge recorders. <br />Characteristics of the Wadge Overburden determined for specific monitoring wells in the permit and adjacent area <br />are s ummari zed in Exhibit 9, Aquifer Test Data. The highest permeability values for the Wadge Overburden (0.3 <br />and 0.6 ft/day) are calculated from observation well data (Wells 006- 82 -74A and 74C), and may reflect effects of <br />using radial -flow theory in a fracture -flow situation. Unless the observation wells are in good communication with <br />the major fractures providing flow to the pumped well, then less drawdown in the observation well will occur and <br />overestimates of permeability from the data will result. Pumped well data are often better indicators of average <br />formation permeability in fracture - dominated systems. <br />PR06 -07 2.04 -25.1 11/07/06 <br />